Yes it's Harry Potter's 20th birthday. Today marks two decades since the first book in the best-selling series hit the stores. So why does it provoke such strong reactions among Christgians?

Some Christians arguing the series is a gospel analogy and others that it promotes a dangerous acceptance of the occult.

John Granger's Looking for God in Harry Potter outlines religious analogies in J.K. Rowling's books while Pope Benedict led a charge denouncing the series.

Raised as a Christian, Rowling herself eventually came out to admit the Christian parallels after the release of Harry Potter and the Deathly Hallows.

'To me, the religious parallels have always been obvious,' she told an audience in America. 'But I never wanted to talk too openly about it because I thought it might show people who just wanted the story where we were going.'

She admitted she struggles herself with belief in any afterlife.

'The truth is that, like Graham Greene, my faith is sometimes that my faith will return. It's something I struggle with a lot,' she told the Tatler magazine in 2006.

'On any given moment if you asked me [if] I believe in life after death, I think if you polled me regularly through the week, I think I would come down on the side of yes — that I do believe in life after death. [But] it's something that I wrestle with a lot. It preoccupies me a lot, and I think that's very obvious within the books.'

Here are three clearly Christian moments in the Harry Potter books.

When she quotes the Bible

The final book overtly quotes the Bible in two separate places.

First of all from Matthew 6.19 on page 325: 'Where you treasure is, there will your heart be also.' Secondly Harry finds 1 Corinthians 15:26 on quoted on his parents tomb stone (page 328): 'The last enemy that shall be destroyed is death.'

When he is rescued by his Father

Dementers are hooded creatures that become symbolic of evil itself through the series. They guard the wizard prison and, when called upon, can give a 'Demontors' Kiss' that removes someone's soul from them – leaving them a shell of a human.

At one point in the third book Harry Potter and the Prisoner of Azkaban,

Harry finds himself surrounded by more than 100 Dementors. Previously unable to do the spell to repel them he finally manages it by saying 'expecto patronum', which means 'in expectation of the father'. A stag – a representative figure of his father – drives the evil beings away to save Harry.

When Harry is 'resurrected'

Perhaps the most obvious moment of Christian symbolism is when Harry 'dies' in order to defeat the last piece of evil.

He discovers in the Deathly Hallows that the final piece of Voldemort's soul rests within him so in order for the enemy to be defeated, Harry has to sacrifice himself to save everyone else.

With parallels to Jesus in the garden of Gethsememe, Harry walks to his death and puts up no fight. After he is killed he meets Dumbledore – a father like figure – who says he has the choice whether to return and defeat ultimately Voldemort which Harry does.